Reinforced freewheeling resilient cover for rotary die-cutting anvil



United States Patent Louis E. Sauer St. Louis, Missouri Application No.: 660,321

Inventor:

Filed: Aug. 14, 1967 Patented: Aug. 4, 1970 Assignee: Centenary Central Inc.

St. Louis, Missouri a Corp. of Missouri REINFORCED FREEWHEELING RE SILIENT COVER FOR ROTARY DIE-CUTTING ANVIL 12 Claims, Drawing Figs.

US. Cl. 83/659, 83/347(Disclosure) Int. Cl. 826d 7/20, B26d 1/56 Field of Search 83/346,

347, 659, 505; 29/130, 132, 123; l0l/4l5.1, 376, 401.3,407;29/148.4R,446,450, 155

[56] References Cited UNITED STATES PATENTS 2,374,194 4/1945 Grupe 29/132 3,213,790 10/1965 McKay.. 10l/415.1 3,274,873 9/1966 Sauer 83/347 Primary Examiner- Andrew R. Juhasz Assistant Examiner James F. Coan Attorney-Kingsland, Rogers, Ezell, Eilcrs and Robbins ABSTRACT: A freewheeling resilient rotary die-cutting anvil cover incorporating a continuous reinforcing insert of corrugated fibreboard, and the like, to prevent binding and subsequent reduction in freewheeling, and for establishing an even cutting pressure over the outer surface of the cover. A modified cover includes a flexible member of one or multiple pieces secured together along a generally axial line or lines and including an annular rib or ribs on the inner surface disposed in annular grooves in the supporting base.

U.S. PATENT 3,522,754

BACKGROUND OF THE INVENTION 1. Field Of The Invention The present invention relates generally to the rotary diecutting art, and more particularly to an improved freewheeling rotary anvil cover used in the cutting of corrugated boxes, and the like.

2. Description OfThe Prior Art In the rotary die-cutting art, rotary anvil constructions employ covers of resilient material, such as rubber, synthetic rubber, polyurethane, and the like, against which the cutting dies work.- Freewheeling covers have been employed, such as that in the applicant's United States Patent No. 3,274,873. However, even in this improved construction of the applicant's patent, under persistent cutting between the ribs of the cover, the bridging portion becomes deformed, and, in effect, raises to cause binding of the ribs in the grooves, thereby reducing and, in many instances, eventually stopping the freewheeling action. In fact, in rotary die setups where the ratio of the cutter and anvil is one to one, upon the sticking of the cover, dust from the cutting action has worked into open cuts in the cover and hardened under further action to such an extent that cutter knives have been broken against the hard surface. Efforts heretofore made in connection with alleviating the problem have been unsuccessful insofar as the applicant knows.

SUMMARY OF THE INVENTION In brief, the present novel reinforced freewheeling anvil cover includes a continous fibreboard, and the like, insert, preferably corrugated for greater strength, which is secured within or to the cover in the molding operation, being located at or adjacent to the inner surface of the cover with the corrugations running axially or transverse to the cover, thereby providing annular flexibility and axial rigidity. A modified cover is of one or more pieces being secured in position by interlocking lugs and recesses and against axial movement by annular interengaging ribs and grooves.

Therefore, objects of the present invention are to provide a novel reinforced freewheeling flexible cover for a rotary die anvil which is an acceptable commercial solution to the present binding problem existing in freewheeling flexible anvil covers, which is of sturdy, long-wearing construction and adapted to further increase the already long life of a freewheeling flexible die-cutting anvil cover, which can be. readily employed in the die-cutting art without expensive manufacturing requirements, and which fulfills the objects and advantages sought therefor. Further objects are to provide an improved freewheeling flexible cover having novel locking and axial movement prevention means which resists binding and permits long freewheeling use.

The foregoing and other objects and advantages are apparent from the following description taken with accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is an end elevation of an anvil employed in rotary die-cutting incorporating the teachings of the present invention, parts being broken away and in section for illustration of details;

FIGURE 2 is a longitudinal, radial cross-sectional view taken on substantially the line 2--2 of FIGURE 1;

FIGURE 3 is a bottom plan view of a segment of corrugated fibreboard employed as an insert;

FIGURE 4 is an enlarged cross-sectional view taken on substantially the line 4--4 of FIGURE 3;

FIGURE 5 is a vertical, transverse cross-sectional view through vertically aligned die-cutting rolls with an anvil of the present invention on the lower roll and the cutting die on the upper roll, a fragment of a paperboard box blank, or the like, illustrated as passing therebetwecn in die-cutting relation;

FIGURE 6 is a cross-sectional view transversely of a modified cover construction;

FIGURE 7 is a cross-sectional view transversely of a resilient cover, such as is shown in the applicants United States Patent No. 3,274,873, illustrating the deformed sagging shape thereof after many hundreds of thousands of cuts;

FIGURE 8 is a view similar to FIGURE 4 of a modified corrugated fiberboard;

FIGURE 9 is a view similar to FIGURE l illustrating a modified cover;

FIGURE I0 is a bottom plan view of FIGURE 9;

FIGURE 1 l is a transverse cross-sectional view on the line 11-11 ofFIGURE 9;

FIGURES 12 and 13 are cross-sectional views taken, respectively, on the lines 12ll2 and 13-13 of FIGURE 10.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings more particularly by reference numerals, 20 indicates generally an anvil employed in rotary die-cutting incorporating the teachings of the present invention, including a base member 22 formed as two halves 24 and 26. Each half 24 and 26 includes annular, peripheral grooves, channels or slots 28 of inverted T-cross section, two being illustrated as formed in the base member 22.

On the base member 22 is a resilient cover 30 comprising two halves 32 and 34 of polyurethane, or other suitable resilient material. Each cover half 32 and 34 includes internally disposed annular ribs 36 of inverted T-cross section which engage in the channels 28. Embedded in each cover half 32 and 34 is a continuous sheet 40 of corrugated fibreboard or the like, which isspaced inwardly of the bottom or inner surface of the cover halves 32 and 34 and extends across the ribs 36, as is clear from FIGURES l and 2. The corrugations run axially or transversely of the cover 30, thereby affording maximum rigidity against the cutting die, yet providing annular flexibility for mounting of the cover halves 32 and 34, and the like. Spaces 42 are employed in molding 30 with the insert sheet 40 spaced as shown in FIGURES l and 2. The cover 30 may comprise a single member or several segments rather than the two halves 32 and 34. A modified sheet 40is illustrated in FIGURE 8 in which the corrugations are more sharply defined.

In FIGURE 6 is shown a modified cover 46 in which the sheet 40 is flush with the bottom or inner surface thereof. Spaced apertures 48 are formed in the fibreboard sheet 40 to tie the annular ribs 36 into the main body of the cover 30 as an integrated structure, if desired. However, test covers 30 of polyurethane made to date have not required the apertures 48. They may be essential with some materials.

In FIGURE 5, the anvil 20 is illustrated as splined on a lower roll 50. Onto an upper roll 52 is splined a cutting die support 54 on which is mounted a cutting rule or blade retainer 56 which retains a cutting rule or blade 58. The cutting rule 58 is illustrated as penetrating the paperboard 60 and cutting a little into the anvil cover 30. Since the anvil cover 30 is annularly movable relative to the anvil base 22, the cutting or gouging effect of the cuttingrule 58 is reduced to a minimum. In fact, anvils constructed in accordance with the principles of the anvil 20 have served continuously in the rotary die cutting of over two and half million box blanks, each box blank taking two cuts, hence, over five million cuts. This is between one hundred and two hundred times the life of resilient anvils heretofore employed.

It is manifest from the foregoing description and the drawings that in the improved reinforced cover 30, the span between the ribs 36 is strengthened to eliminate raising of the nature illustrated in FIGURE 7 of the drawings. There can be no outward or spreading vector on the ribs 36 to cause binding and ultimate freezing of the cover 30 against annular movement, as with the cover of FIGURE 7. Additionally, the disposition of the reinforcing sheet 40 over the ribs 36 establishes an even cutting pressure across the outer surface of the cover 30. It is clear that even if a major part of the penetration of the dies is between the ribs 36 and a little concavity develops in this area, there will be no outward effect on the ribs 36 to cause binding.

In FIGURES 9-13 is a rotary anvil 70 including a base member 72 formed as two halves 74 and 76. Each half 74 and 76 includes an annular groove 78 of the cross section illustrated. A one-piece resilient cover 80 of polyurethane, or other suitable material is disposed on the base member 72. The cover 80 may be in two or more pieces. The cover 80 has an annular rib 82 disposed in the groove 78 comfortably filling it so there is no depressive effect radially inwardly of the anvil 70 caused by a gap. At one end of the cover 80 are alternating lugs 84 and recesses 86 and at the other end alternating lugs 86 shaped to engage in the recesses 86' and recesses 84' shaped to receive the lugs 84. The end edges 88 of the lugs 84 and 86 are convex and the inner edges 90 of the recesses 84 and 86' are concave. A transition from convex to concave occurs about midway between ends 88 and inner edges 90. A fibreboard sheet 40 or 40 may be included in the cover 80.

The foregoing anvil 70 substantially eliminates binding without the use of the sheet 40 or 40, since the rib 82 bottoms in the groove 78. However, the addition of 40 and 40' will offset the natural tendency of the cover to raise after a number of cuts have been made. In order to insure this nonbinding result, the cover 80 may be a little loose on the base member 72. The interlocking lugs 84, 86 and recesses 84', 86' provide a firm securing means for the cover 80.

Hence, it is palpable that there have been provided novel improved reinforced covers for rotary die-cutting anvils which fulfill the objects and advantages sought therefor.

it is to be understood that the foregoing description and the accompanying drawings have been given by way of illustration and example. It is also to be understood that changes in form of the elements, rearrangement of parts, and substitution of equivalent elements, which will be obvious to those skilled in the art, are contemplated as within the scope ofthe present invention which is limited only by the claims which follow.

lclaim:

l. A cover member for a rotary anvil used in rotary diecutting of box blanks, and the like, comprising, in combination, an annular main body of flexible material, means operatively associated with said main body for mounting said cover member on a base for annular movement bodily in respect thereto, and reinforcing means secured to said main body below the outer surface thereof strengthening the cover member and substantially preventing axial deformation thereof from long use in rotary die-cutting operations, said reinforcing means including a continuous corrugated fibreboard sheet, and the like, the corrugations of said sheet running transversely of said cover member, said sheet being disposed between said mounting means and the major portion of the main body, said mounting means including at least two spaced apart annular ribs, said sheet extending transversely between said ribs to provide a rigid support for the resilient main body portion thereabove.

2. A cover member for a rotary anvil used in rotary diecutting of box blanks, and the like, comprising, in combination, an annular main body of flexible material, means operatively associated with said main body for mounting said cover member on a base for annular movement bodily in respect thereto, and reinforcing means secured to said main body below the outer surface thereof strengthening the cover member and substantially preventing axial deformation thereof from long use in rotary die-cutting operations, said reinforcing means including a continuous corrugated fibreboard sheet, and the like, the corrugations of said sheet running transversely of said cover member, said sheet being embedded in and coplanar with the lower surface of said main body and in which said mounting means is secured directly to said sheet.

3. The combination of Claim 2 in which said sheet includes apertures therethrough in areas between said mounting means and said main body, said mounting means and said main body being of the same material and integrated by the same material in said apertures.

4. A cover member for a rotary anvil used in rotary diecutting of box blanks, and the like, comprising a single elongated resilient flexible sheet adapted to be disposed on an annular base for relative free annular movement, a longitudinal rib on the inner side thereof adapted to engage in an annular recess on an annular base, and alternating interlocking lugs and recesses at each end of said sheet adapted to be axially disposed when said cover member is on an annular base.

5. The cover of Claim 4 in which one of said lugs and recesses has a convex edge and the other an engaging concave edge. I

6. A cover for a rotary anvil used in rotary die-cutting of box blanks, and the like, comprising a single elongated resilient flexible sheet adapted to be disposed on an annular base for relative free annular movement, a longitudinal rib on the inner side thereof adapted to engage in an annular recess on an annular base, and alternating interlocking lugs and recesses at each end of said sheet engageable and disengageable without elongation of said cover adapted to hold the cover on and about an annular base.

7. The cover of Claim 6 in which one of said lugs and recesses has a convex edge and the other an engaging concave edge.

8. A rotary anvil used in rotary die cutting of paperboard comprising, in combination, an annular base, an annular groove in said base of substantially U-cross section, and the like, and a split cover of resilient flexible material on said base including a rib on the underside thereof in said groove of the base, and at least one interlocking means holding ends of the cover firmly together to maintain said cover on said base in freewheeling relation, said interlocking means being engageable and disengageable without elongation of said cover.

9. The combination of Claim 8 in which said interlocking means comprises interengaging lugs and complementary recesses.

10. The combination of Claim 9 in which one of said lugs and recesses has a convex edge and the other an engaging concave edge.

11. The cover member of Claim 4 in which said alternating interlocking lugs and recesses are engageable and disengageable to mount said cover member on and to remove said cover member from an annular base without removing the annular base from its support.

12. The rotary anvil of Claim 8 in which said interlocking means are engageable and disengageable to mount said cover on and to remove said cover from said annular base without removing said annular base from its support. 

